Re: [Qemu-devel] [RFC PATCH v4 00/28] COarse-grain LOck-stepping(COLO) Virtual Machines for Non-stop Service

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
> This is the 4th version of COLO, here is only COLO frame part, include: VM checkpoint,
> failover, proxy API, block replication API, not include block replication.
> The block part has been sent by wencongyang:
> [RFC PATCH COLO v2 00/13] Block replication for continuous checkpoints
> 
> Compared with last version, there aren't too much optimize and new functions.
> The main reason is that there is an known issue that still unsolved, we found
> some dirty pages which have been missed setting bit in corresponding bitmap.
> And it will trigger strange problem in VM.
> We hope to resolve it before add more codes.
> 
> You can get the newest integrated qemu colo patches from github:
> https://github.com/coloft/qemu/commits/colo-v1.1

I thought I'd just say I've got the remotes/origin/colo_huawei_v4.7 off Wen's
git running here on one of my pair of machines.

This set of hosts is mostly OK running colo; the proxy module still gets
upset sometimes; but mostly on errors;  if the colo-proxy-script fails
during startup, I get RCU stalls; but if the script works, colo normally
works on this setup.

Dave

> About how to test COLO, Please reference to the follow link.
> http://wiki.qemu.org/Features/COLO.
> 
> Please review and test.
> 
> Known issue still unsolved:
> (1) Some pages dirtied without setting its corresponding dirty-bitmap.
> 
> Previous posted RFC patch series:
> http://lists.nongnu.org/archive/html/qemu-devel/2014-06/msg05567.html
> http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg04459.html
> https://lists.gnu.org/archive/html/qemu-devel/2015-02/msg04771.html
> 
> TODO list:
> 1 Optimize the process of checkpoint, shorten the time-consuming:
>   (Partly done, patch is not include into this series)
>    1) separate ram and device save/load process to reduce size of extra memory
>       used during checkpoint
>    2) live migrate part of dirty pages to slave during sleep time.
> 2 Add more debug/stat info
>   (Partly done, patch is not include into this series)
>   include checkpoint count, proxy discompare count, downtime,
>    number of live migrated pages, total sent pages, etc.
> 3 Strengthen failover
> 4 optimize proxy part, include proxy script.
> 5 The capability of continuous FT
> 
> v4:
> - New block replication scheme (use image-fleecing for sencondary side)
> - Adress some comments from Eric Blake and Dave
> - Add commmand colo-set-checkpoint-period to set the time of periodic checkpoint
> - Add a delay (100ms) between continuous checkpoint requests to ensure VM
>   run 100ms at least since last pause.
> 
> v3:
> - use proxy instead of colo agent to compare network packets
> - add block replication
> - Optimize failover disposal
> - handle shutdown
> 
> v2:
> - use QEMUSizedBuffer/QEMUFile as COLO buffer
> - colo support is enabled by default
> - add nic replication support
> - addressed comments from Eric Blake and Dr. David Alan Gilbert
> 
> v1:
> - implement the frame of colo
> 
> Wen Congyang (1):
>   COLO: Add block replication into colo process
> 
> zhanghailiang (27):
>   configure: Add parameter for configure to enable/disable COLO support
>   migration: Introduce capability 'colo' to migration
>   COLO: migrate colo related info to slave
>   migration: Integrate COLO checkpoint process into migration
>   migration: Integrate COLO checkpoint process into loadvm
>   COLO: Implement colo checkpoint protocol
>   COLO: Add a new RunState RUN_STATE_COLO
>   QEMUSizedBuffer: Introduce two help functions for qsb
>   COLO: Save VM state to slave when do checkpoint
>   COLO RAM: Load PVM's dirty page into SVM's RAM cache temporarily
>   COLO VMstate: Load VM state into qsb before restore it
>   arch_init: Start to trace dirty pages of SVM
>   COLO RAM: Flush cached RAM into SVM's memory
>   COLO failover: Introduce a new command to trigger a failover
>   COLO failover: Implement COLO master/slave failover work
>   COLO failover: Don't do failover during loading VM's state
>   COLO: Add new command parameter 'colo_nicname' 'colo_script' for net
>   COLO NIC: Init/remove colo nic devices when add/cleanup tap devices
>   COLO NIC: Implement colo nic device interface configure()
>   COLO NIC : Implement colo nic init/destroy function
>   COLO NIC: Some init work related with proxy module
>   COLO: Do checkpoint according to the result of net packets comparing
>   COLO: Improve checkpoint efficiency by do additional periodic
>     checkpoint
>   COLO: Add colo-set-checkpoint-period command
>   COLO NIC: Implement NIC checkpoint and failover
>   COLO: Disable qdev hotplug when VM is in COLO mode
>   COLO: Implement shutdown checkpoint
> 
>  arch_init.c                            | 199 +++++++-
>  configure                              |  14 +
>  hmp-commands.hx                        |  30 ++
>  hmp.c                                  |  14 +
>  hmp.h                                  |   2 +
>  include/exec/cpu-all.h                 |   1 +
>  include/migration/migration-colo.h     |  58 +++
>  include/migration/migration-failover.h |  22 +
>  include/migration/migration.h          |   3 +
>  include/migration/qemu-file.h          |   3 +-
>  include/net/colo-nic.h                 |  25 +
>  include/net/net.h                      |   4 +
>  include/sysemu/sysemu.h                |   3 +
>  migration/Makefile.objs                |   2 +
>  migration/colo-comm.c                  |  80 ++++
>  migration/colo-failover.c              |  48 ++
>  migration/colo.c                       | 809 +++++++++++++++++++++++++++++++++
>  migration/migration.c                  |  60 ++-
>  migration/qemu-file-buf.c              |  58 +++
>  net/Makefile.objs                      |   1 +
>  net/colo-nic.c                         | 438 ++++++++++++++++++
>  net/tap.c                              |  45 +-
>  qapi-schema.json                       |  42 +-
>  qemu-options.hx                        |  10 +-
>  qmp-commands.hx                        |  41 ++
>  savevm.c                               |   2 +-
>  scripts/colo-proxy-script.sh           |  97 ++++
>  stubs/Makefile.objs                    |   1 +
>  stubs/migration-colo.c                 |  58 +++
>  vl.c                                   |  36 +-
>  30 files changed, 2178 insertions(+), 28 deletions(-)
>  create mode 100644 include/migration/migration-colo.h
>  create mode 100644 include/migration/migration-failover.h
>  create mode 100644 include/net/colo-nic.h
>  create mode 100644 migration/colo-comm.c
>  create mode 100644 migration/colo-failover.c
>  create mode 100644 migration/colo.c
>  create mode 100644 migration/colo.c.
>  create mode 100644 net/colo-nic.c
>  create mode 100755 scripts/colo-proxy-script.sh
>  create mode 100644 stubs/migration-colo.c
> 
> -- 
> 1.7.12.4
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK